Table 4:

Comparison of diagnostic criteria and outcomes

	Diffuse Intracranial Dolichoectasia	Vertebrobasilar Dolichoectasiaa
Imaging appearance	Fusiform aneurysmal dilation of an entire vascular segment (ie, supraclinoid ICA, basilar artery, M1 segment of the MCA)	Fusiform: aneurysmal dilation without definable neck involving a portion of an arterial segment with any degree of tortuosity Dolichoectatic: uniform aneurysmal dilation of an artery involving the entire basilar or vertebral or both with any degree of tortuosity Transitional: uniform aneurysmal dilation of an artery with superimposed dilation of a portion of the involved arterial segment
Distribution	≥2 Intracranial vascular beds (ie, vertebrobasilar system, left anterior circulation, or right anterior circulation)	Vertebrobasilar system only
Size criteria	Cavernous ICA: ≥8.5 mm Supraclinoid ICA: ≥8.0 mm MCA: ≥5.0 mm Basilar artery: ≥6.0 mm	Basilar artery diameter of >5.0 mm
Growth rate	10%/year	7%/year2,10
Ischemic stroke risk	11%/year	3%/year2,10
Aneurysm rupture risk	6%/year	2%/year2,10

^aDefinitions of vertebrobasilar dolichoectasia proposed by Flemming et al.²